👤

Sin 2013π=?
sin 23π /2=?
cos 25π/4=?
E=sin 45° + cos 60° / cos 45°- sin 60°


Răspuns :

sin 2013π=sinπ=0

sin23π/2=sin(-π/2)=-sin π/2=-1
sau sin 23π/2= sin 3π/2=-1

cos 25π/4=cosπ/4=√2/2
 am folosit perioada 2π,  si multiplii acesteia, 10π si, respectiv, 6π

 [√2/2+√3/2]/(√2/2-√3/2)=(√3+√2)/ (√3-√2)=(√3+√2)²/(3-2)=5+2√6